It is well known that patients who are confined to a bed or chair for extended periods of time are at risk of developing decubitus ulcers, i.e., pressure sores, or bed sores as they are more commonly known. These ulcers are often seen to develop within soft tissue that is compressed between a bed or chair surface and a patient's weight-bearing bony prominences, the compressed tissue being at least partially of deprived of oxygenated blood flow. A continued lack of blood flow, and resultant lack of oxygen, can result in cell death, which may be evidenced in the form of pressure sores. Pressure sores do not develop immediately, but rather form over time, with the development speed depending on a number of factors including the firmness and friction of the supporting surface against the patient's skin, the patient/ambient temperature, the amount of moisture in contact with the skin, and the health and susceptibility of the skin due to age, illness, and/or nutrition.
One venerable and generally accepted means of reducing the risk of decubitus ulcer development in bedfast patients is to turn them regularly, usually at approximately two hour intervals. For example, a patient in a back rest position might be periodically rolled to one side or the other, such motion helping to maintain blood flow to soft tissue that is under compression. Similar strategies are employed for patients that are confined to a chair for long periods of time. Obviously, an assisted-movement strategy relies largely on the vigilance of the (often harried) attending staff to insure that the patient is properly relocated. Further, it is far too easy for the busy caregiver to let the time for turning the patient slip by in the press of other daily emergencies. To the extent that the caregiver is too busy or forgets to perform this service, this method can fail to achieve its purpose. Further, this sort of strategy can be counterproductive for use with the patient that has some capacity for self-movement when, for example, the patient may have turned himself just before the caregiver arrived to manually turn him, in which case the caregiver will likely place the patient back in the position from which he recently moved, thus inadvertently exacerbating the problem. Further, after being rolled to a new position the patient might return to the original “comfortable” position after the caregiver leaves which would obviously negate the effects of the reposition.
The process of moving a patient to another position is admittedly disruptive to the patient and this is especially true at night, since the patient—if he or she were sleeping—will be awakened for the purpose of relocation. The typical two-hour movement interval must be observed around the clock if the method is to be effective, so it is necessary to disturb the patient—who might be sleeping soundly at the time—to make the required adjustment in position. Further, this adjustment might not have even been necessary, or even counter indicated, if the patient had recently moved of his or her own volition. Thus, in many situations it would be advantageous for the caregiver to know if and when the patient last moved his or herself. Then, if the last movement were within a prescribed period of time, it might be possible to spare the patient an unnecessary interruption in his or her healing sleep. The caregiver would then relocate the sleeping patient, only if that relocation were actually required. Further, knowing which patients do not need to be moved could result in a substantial savings in labor costs, as the time that would otherwise be devoted to moving the patient that did not actually need to be moved could be productively applied elsewhere. That being said, as useful as this sort of information might be to the health care provider, however, the present state-of-the-art in patient management does not provide this sort information.
Generally speaking, there are two broad approaches to dealing with decubitus ulcers: mechanical and medicinal. The medical approach is concerned with the development of medicinal compounds and methods for treating the ulcer after it occurs. This approach is obviously quite useful but ultimately it is reactive, rather than proactive, because it attempts to minimize the damage occasioned by the ulcer after it has formed.
On the other hand, the mechanical approach typically utilizes a specialized mattress, pad, or other arrangement, which is designed to lessen the weight-pressure that is brought to bear on the patient's bony prominences. These devices might be either static (e.g., foam, air, or water mattresses) or dynamic (e.g., compartmentally inflatable mattresses that dynamically shift the locus of support pressure under the patient over time. Examples of inventions in the prior art that are generally concerned with this subject matter include U.S. Pat. Nos. 4,425,676, 5,926,884, and 5,072,468, the disclosures of which are incorporated herein by reference. Generally speaking, a mechanical approach is to be preferred because it seeks to spare the patient the discomfort and risk associated with bed sores and reduces the costs associated with treating such, which costs can potentially accrue to the facility under some circumstances.
One enhanced variant of the mechanical approach utilizes a proactive strategy that seeks to avoid tissue death by using a combination of automatic monitoring of the patient's movement together with notification of a caregiver if the patient's movement pattern does not meet or exceed some predetermined level. Upon receipt of such notice, the caregiver will then manually turn the patient, as has been the custom heretofore. This approach, if properly implemented, has the potential to dramatically reduce the risk of pressure sores while keeping the cost of such preventative measures within the reach of small institutions and individual patients.
It is this last approach, electronic patient monitoring combined with caregiver intervention, which has been adopted by the instant inventors. As such, general information relating to mat-type sensors and electronic monitors for use in patient monitoring is relevant to the instant disclosure and may be found in U.S. Pat. Nos. 4,179,692, 4,295,133, 4,700,180, 5,600,108, 5,633,627, 5,640,145, 5,654,694, and 6,111,509 (the last of which concerns electronic monitors generally). Additional information may be found in U.S. Pat. Nos. 4,484,043, 4,565,910, 5,554,835, 5,623,760, 6,417,777 (sensor patents) and U.S. Pat. No. 5,065,727 (holsters for electronic monitors), the disclosures of all of which patents are all incorporated herein by reference. Further, U.S. Pat. No. 6,307,476 (discussing a sensing device which contains a validation circuit incorporated therein), U.S. Pat. No. 6,544,200, (for automatically configured electronic monitor alarm parameters), and U.S. patent Ser. No. 09/878,088 (for a binary switch and a method of its manufacture), and Ser. No. 10/125,059 (for a lighted splash guard) are similarly incorporated herein by reference.
Additionally, sensors other than mat-type pressure sensing switches may be used in patient monitoring including, without limitation, temperature sensors, patient activity sensors, toilet seat sensors (see, e.g., U.S. Pat. No. 5,945,914), wetness sensors (e.g., U.S. Pat. No. 6,292,102), decubitus ulcer sensors (e.g., U.S. Pat. No. 6,646,556), etc., all of which are incorporated herein by reference. Thus, in the text that follows the terms “mat” or “patient sensor” should be interpreted in its broadest sense to apply to any sort of patient monitoring switch or device, whether the sensor is pressure sensitive or not.
Finally, pending U.S. patent application Ser. No. 10/397,126, also incorporated herein by reference, discusses how white noise can be used in the context of decubitus ulcer prevention.
Heretofore, as is well known in the patient monitoring and, more particularly, the decubitus ulcer prevention arts, there has been a need for an invention to address and solve the above-described problems. Accordingly, it should now be recognized, as was recognized by the present inventors, that there exists, and has existed for some time, a very real need for a system for monitoring patients that would address and solve the above-described problems.
Before proceeding to a description of the present invention, however, it should be noted and remembered that the description of the invention which follows, together with the accompanying drawings, should not be construed as limiting the invention to the examples (or preferred embodiments) shown and described. This is so because those skilled in the art to which the invention pertains will be able to devise other forms of this invention within the ambit of the appended claims.